Acute vestibular syndrome associated with anti-GQ1b antibody

Objectives To delineate the clinical features and ocular motor findings in acute vestibular syndrome (AVS) associated with anti-GQ1b antibodies. Methods We reviewed 90 patients with positive serum anti-GQ1b antibody in association with various neurological syndromes at Seoul National University Bundang Hospital from 2004 to 2018. The diagnoses included typical Miller Fisher syndrome (n = 31), acute ophthalmoplegia without ataxia (n = 27), Guillain-Barre syndrome with ophthalmoplegia (n = 18), AVS (n = 11), and Bickerstaff brainstem encephalitis (n = 3). Of them, the 11 patients with AVS formed the basis of this study. We also conducted a systematic review on AVS reported in association with anti-GQ1b antibody. Results Patients with AVS showed various ocular motor findings that included head-shaking nystagmus (n = 6), spontaneous nystagmus (n = 5), gaze-evoked nystagmus (n = 5), central positional nystagmus (n = 3), canal paresis (n = 2), and abnormal head-impulse tests (n = 1) without any internal or external ophthalmoplegia. Compared to those with other subtypes, patients with AVS mostly showed normal deep tendon reflexes (8 of 11 [73%], p = 0.002) and normal results on nerve conduction studies (4 of 4 [100%], p = 0.010). The clinical and laboratory findings resolved or improved markedly in all patients within 6 months of symptom onset. Systematic review further identified 7 patients with AVS and positive serum anti-GQ1b antibody who showed various ocular motor findings, including gaze-evoked nystagmus, saccadic dysmetria, central positional nystagmus, and ocular flutter or opsoclonus. Conclusion Anti-GQ1b antibody may cause acute vestibulopathy by involving either the central or peripheral vestibular structures. AVS may constitute a subtype of anti-GQ1b antibody syndrome.